使用javaScript实现处理散列表的冲突的方法之分离链接

function defaultToString(item){
    if(item == null){
        return 'null';
    }
    if(item == undefined){
        return 'undefined';
    }
    if(typeof item == "string" || item instanceof  String){
        return `${item}`;
    }
    return item.toString();
}
class ValuePair{
    constructor(key,value){
        this.key = key;
        this.value = value;
    }
}
class Node{
    constructor(element,next){
        this.element = element;
        this.next = next;
    }
}
class LinkedList{
    constructor(){
        this.head = undefined;
        this.count = 0;
    }
    isEmpty(){
        return this.size() == 0;
    }
    size(){
        return this.count;
    }
    push(element){
        let node = new Node(element);
        if(this.head == undefined){
            this.head = node;
        }else{
            let current = this.head;
            while(current.next!=null){
                current = current.next;
            }
            current.next = node;
        }
        this.count++;
    }
    remove(element){
        let index = this.indexOf(element);
        this.removeAt(index);
    }
    removeAt(index){
        if(index>=0 && index < this.count){
            let current = this.head;
            if(index == 0){
                if(this.count == 1){
                    this.head = undefined;
                }else{
                    this.head = current.next;
                }
            }else{
                let previous = this.getElementAt(index - 1);
                current = previous.next;
                previous.next = current.next;
            }
            this.count--;
        }
        return ''
    }
    getHead(){
        if(this.head!=undefined){
            return this.head;
        }
        return 'null';
    }
    indexOf(element){
        let current = this.head;
        for(let i =0; i < this.count; i++){
            if(current.element === element){
                return i;
            }
            current = current.next;
        }
    }
    getElementAt(index){
        if(index>=0 && index< this.count){
            let current = this.head;
            for(let i = 0; i < index; i++){
                current = current.next;
            }
            return current;
        }
        return -1;
    }
    insert(element,position){
        if(position >= 0&& position <= this.count){
            let node = new Node(element);
            let previous = this.getElementAt(position - 1);
            if(position == 0){
               if(this.head == undefined){
                   this.head = node;
               }else{
                   node.next = this.head;
                   this.head = node;
               }
            }else if(position == this.count){
                previous.next = node;
            }else{
                let current = previous.next;
                node.next = current;
                previous.next = node;
            }
            this.count++;
        }
        return ''
    }
    toString(){
        let current = this.head.next;
        let objString = this.head.element;
        for(let i = 1; i < this.count; i++){
            objString = `${objString},${current.element}`;
        }
        return objString;
    }
}

class HashTableSpeparateChaining{
    constructor(toStrFn = defaultToString){
        this.toStrFn = toStrFn;
        this.table = {};
    }
    loseloseHashCode(key){
        if(typeof key == 'number'){
            return key;
        }
        let str = this.toStrFn(key);
        let addr = 0;
        for(let i = 0; i < str.length;i++){
            addr += str.charCodeAt(i);
        }
        return addr % 37;
    }
    hashCode(key){
        return this.loseloseHashCode(key);
    }
    put(key,value){
        if(key != null && value != null){
            let valuePair =new ValuePair(key,value);
            const position = this.hashCode(key);
            if(this.table[position] == null){
                this.table[position] = new LinkedList();
            }
            this.table[position].push(valuePair);
            return true;
        }
        return false;
    }
    get(key){
        const position = this.hashCode(key);
        const linkedList = this.table[position];
        if(linkedList != null && !linkedList.isEmpty()){
            let current = linkedList.getHead();
            while(current!=null){
                if(current.element.key == key){
                    return current.element.value;
                }
                current = current.next;
            }
        }
        return undefined;
    }
    remove(key){
        const position = this.hashCode(key);
        const linkedList = this.table[position];
        if(this.table[position] != null && !linkedList.isEmpty()){
            let current = linkedList.getHead();
            let previous = null;
            for(let i = 0 ; i < linkedList.size(); i++){
              if(current.element.key == key){
                  if(previous == null){
                    linkedList.head = current.next;
                  }else{
                      previous.next = current.next;
                  }
              }
              previous = current;
              current = current.next;
            }
            return true;
        }
        return false;
    }
}